Firm's Fortunes in 2014 Could Rest on Sales of Antibiotic Doxycycline

Talk about a shot in the arm: The market value of Hikma Pharmaceuticals has doubled in little more than a year. Yet the company may find it difficult to maintain the euphoric feeling.

The swift share-price rise, up nearly 40% just this year, has left the London-listed maker of generic drugs trading at 24 times forecast 2014 earnings. That is well above Hikma's average multiple over five years in the high teens and is about 1.5 times...